FIG. 1 is a schematic of a conventional nuclear power station containment building 36 that houses a reactor pressure vessel 42 with various configurations of fuel 41 and reactor internals for producing nuclear power. Reactor 42 sits in a drywell 51, including upper drywell 54 and a lower drywell 3 that provides space surrounding and under reactor 42 for external components and personnel. Several different pools and flowpaths constitute an emergency core coolant system inside containment 36 to provide fluid coolant to reactor 26 in the case of a transient involving loss of cooling capacity in the plant.
For example, containment 36 may include a pressure suppression chamber 58 surrounding reactor 42 in an annular or other fashion and holding suppression pool 59. Suppression pool 59 may include an emergency steam vent used to divert steam into suppression pool 59 for condensation and heat sinking, to prevent over-heating and over-pressurization of containment 36. Suppression pool 59 may also include flow paths that allow fluid flowing into drywell 54 to drain, or be pumped, into suppression pool 59. Suppression pool 59 may further include other heat-exchangers or drains configured to remove heat or pressure from containment 36 following a loss of coolant accident. An emergency core cooling system line and pump 10 may inject coolant from suppression pool 59 into reactor 42 in order to make up lost feedwater and/or other emergency coolant supply.
Lines taking coolant from suppression pool 59, either for injection into reactor 42 via ECCS line 10 or for heat exchanging outside containment 36 or other uses, conventionally use an intake strainer in suppression pool 59 to filter debris found in suppression pool 59. For example, US Patent Publication 2011/0215059 to Carr et al. and 2006/0219645 to Bilanin et al., discuss strainers submerged and used in suppression pool 59 to prevent debris from entering ECCS pumps and reactor 42. The US NRC's “Resolution of Generic Safety Issues: Issue 191: Assessment of Debris Accumulation on PWR Sump Performance (Rev. 2) (NUREG-0933, Main Report with Supplements 1-34)” of Mar. 29, 2012 further discusses the effects of debris from suppression pool 59 on reactor and emergency system chemistry and operation. The disclosures of each of these publications are incorporated herein in their entireties.
As shown in FIG. 1, other emergency cooling systems are useable with reactor 42, including a gravity-driven cooling system pool 37 that can further provide coolant to reactor 42 via piping 57 and/or a passive containment cooling system pool 65. Any or all discussed safety system may be used alone or in any combination in various reactor designs, each to the effect of preventing overheating and damage of core 41, reactor 42 and all other structures within containment 36 by supplying necessary coolant, removing heat, and/or reducing pressure.